XML (de)serialization invalid string inconsistent in c#?

Question

In C# (.net 4.0 and 4.5 / vs2010 and vs12) when I serialize an object containing a string having an illegal character using XMLSerializer, no error is thrown. However, when

Answer 1

1.

You can set XmlWriterSettings's CheckCharacters property to avoid writing illegal chars.(Serialize method would throw exception)

using (FileStream tmpFileStream = new FileStream(tmpFile, FileMode.OpenOrCreate, FileAccess.ReadWrite))
{
    var writer = XmlWriter.Create(tmpFileStream, new XmlWriterSettings() { CheckCharacters = true});
    serializer.Serialize(writer, items);
}

2.

You can create your own XmlTextWriter to filter out unwanted chars while serializing

using (FileStream tmpFileStream = new FileStream(tmpFile, FileMode.OpenOrCreate, FileAccess.ReadWrite))
{
    var writer = new MyXmlWriter(tmpFileStream);
    serializer.Serialize(writer, items);
}

public class MyXmlWriter : XmlTextWriter
{
    public MyXmlWriter(Stream s) : base(s, Encoding.UTF8)
    {
    }

    public override void WriteString(string text)
    {
        string newText = String.Join("", text.Where(c => !char.IsControl(c)));
        base.WriteString(newText);
    }
}

3.

By creating your own XmlTextReader you can filter out unwanted chars while deserializing

using (FileStream plainTextFile = new FileStream(tmpFile, FileMode.Open, FileAccess.Read))
{
    var reader = new MyXmlReader(plainTextFile);
    result = (SomeObject)serializer.Deserialize(reader); 
}

public class MyXmlReader : XmlTextReader
{
    public MyXmlReader(Stream s) : base(s)
    {
    }

    public override string ReadString()
    {
        string text =  base.ReadString();
        string newText = String.Join("", text.Where(c => !char.IsControl(c)));
        return newText;
    }
}

4.

You can set XmlReaderSettings's CheckCharacters property to false. Deserialization will work now smoothly. (you'll get \v back.)

using (FileStream plainTextFile = new FileStream(tmpFile, FileMode.Open, FileAccess.Read))
{
    var reader = XmlReader.Create(plainTextFile, new XmlReaderSettings() { CheckCharacters = false });
    result = (SomeObject)serializer.Deserialize(reader); 
}